The People That Claim To Know say that deer whistles are useless. I have never hit a deer with my Dodge/Cummins, my theory is that the truck makes enough noise to scare them off-or maybe I just don't drive enough.

I have never hit a deer I saw-every deer I have hit just appeared as if from nowhere on my bumper. No time to react, FLASH and they were there.

The 1/4 mile in front of our house has claimed 7 deer in the past year-that I know of.